It is desirable in both military and commercial applications and particularly in fiber optic systems incorporating pulsed semiconductor laser diodes, that the lasing elements emit a stable frequency spectrum. It is well known that the use of semiconductor laser diodes has been limited due to the characteristic impurity of the lasing spectra of known laser diode products. The causes of the spectral impurities have remained unknown.
It is taught in a related disclosure, U.S. Pat. No. 4,688,076, issued in the name of the present inventor to the same assignee of record, that the presence and reverberations of thermoelastic waves in semiconductor diode lasers cause undesirable spectral modulation of the emitted light spectra. The pending application discloses a laser diode heat sink which avoids disturbance of the laser diode output by shaping, contouring and texturing of the heat sink material and geometry to avoid focussing of elastic waves back upon the laser diode. It is also taught in the pending application that the heat sink may be coated with a viscoelastic material to attenuate elastic waves impinging on the surface of the heat sink.